Based on the Heap Sort code in 'Numerical Recipes in C' by William H.
Press, Brian P. Flannery, Saul A. Teukolsky, and William T. Vetterling,
Cambridge University Press, 1990, ISBN 0-521-35465-X.

The MIPS rating is based upon the program run time (runtime) for one
iteration and a gcc 2.1 unoptimized (gcc -DUNIX) assembly dump count of
instructions per iteration for a i486 machine (assuming 80386 code).  This
is the reference used.

The maximum amount of memory allocated is based on the 'imax' variable in
main(). Memory size = (2000*sizeof(long))*2^imax. imax is currently set to
8, but this value may be increased or decreased depending upon your system
memory limits. For standard Intel PC CPU machines a value of imax = 3 must
be used else your system may crash or hang up despite code in the program
to prevent this.